[mutter] cogl-path: Cast function pointer explicitly

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit d4a9535f04b4b230c1dd41285c0bd4bba18f8616
Author: Jonas Ådahl <jadahl gmail com>
Date:   Sun Jan 20 11:35:27 2019 +0100

    cogl-path: Cast function pointer explicitly
    
    gluTessCallback() expects an equivalent to a GFunc, but we pass
    functions with arguments without casting. To get rid of warnings, cast
    the callback function pointer to the expected type.

 cogl/cogl-path/cogl-path.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/cogl/cogl-path/cogl-path.c b/cogl/cogl-path/cogl-path.c
index 8adf54257..28aeed64a 100644
--- a/cogl/cogl-path/cogl-path.c
+++ b/cogl/cogl-path/cogl-path.c
@@ -1358,13 +1358,13 @@ _cogl_path_build_fill_attribute_buffer (CoglPath *path)
   gluTessNormal (tess.glu_tess, 0.0, 0.0, 1.0);
 
   gluTessCallback (tess.glu_tess, GLU_TESS_BEGIN_DATA,
-                   _cogl_path_tesselator_begin);
+                   (GCallback) _cogl_path_tesselator_begin);
   gluTessCallback (tess.glu_tess, GLU_TESS_VERTEX_DATA,
-                   _cogl_path_tesselator_vertex);
+                   (GCallback) _cogl_path_tesselator_vertex);
   gluTessCallback (tess.glu_tess, GLU_TESS_END_DATA,
-                   _cogl_path_tesselator_end);
+                   (GCallback) _cogl_path_tesselator_end);
   gluTessCallback (tess.glu_tess, GLU_TESS_COMBINE_DATA,
-                   _cogl_path_tesselator_combine);
+                   (GCallback) _cogl_path_tesselator_combine);
 
   gluTessBeginPolygon (tess.glu_tess, &tess);